So I just went to feed my boys, and today I noticed that Volker's gill isn't closing on one side, an is in face sticking out a bit. He seems active and healthy otherwise, but at first i thought he was thinking about flaring at me. then I realized... it's just not going in. Volker is def a favorite of mine, and I'm worried about him now. 8C The only thing I've got on hand is aquarium salt.

EDIT: Okay so I went back and looked the tank over, wondering if maybe he'd hurt himself. I spot one of the teeny snails, but it looked a little wrong. It was dead (and kinda stinky). It's late and people are sleeping, or I'd do a water change right now. 8C Could this have made Volker sick?

Housing
What size is your tank? 10 gallons.
What temperature is your tank? 80 degrees
Does your tank have a filter? No
Does your tank have an air stone or other type of aeration? No
Is your tank heated? Yes
What tank mates does your betta fish live with? Two other male bettas-- divided. Two apple snails, two small snails (about as big as an eraser each), and four ghost shrimp.)

Food
What type of food do you feed your betta fish? New Life Spectrum Betta Formula
How often do you feed your betta fish? Once a day, 3-5 pellets

Maintenance
How often do you perform a water change? Once a week
What percentage of the water do you change when you perform a water change? 50% or 100%, every other water chance
What type of additives do you add to the water when you perform a water change? Prime water conditioner

Water Parameters:
Have you tested your water? If so, what are the following parameters?

Nope 8C

Ammonia:
Nitrite:
Nitrate:
pH:
Hardness:
Alkalinity:

Symptoms and Treatment
How has your betta fish's appearance changed? Gill on one side will not close all the way.
How has your betta fish's behavior changed? It hasn't so far.
When did you start noticing the symptoms? Tonight.
Have you started treating your fish? If so, how? No, considering isolating in a cup and floating.
Does your fish have any history of being ill? Not that I know of
How old is your fish (approximately)? No clue, he was a petco fish

It could be an injury, something stuck in the gill plate or even scar tissue from an old injury or ammonia burns...hard to say.....I wouldn't do anything at this point unless he is having trouble breathing.....good that you made a water change.....

I would increase the water changes to twice weekly 50% and 1 monthly 100% on an unfiltered 10gal with that bioload to maintain water quality......unless you have lots of live active growing plants.....

Just an update-- Volker's doing fine as far as breathing goes and all. Very active and healthy. The gill doesn't appear to be sticking out quite as far-- but it's still sticking out a bit. I'm quite puzzled, and still a little worried, but he seems fine.